It's a good thing horsepower isn't fattening, because I've been pigging out on 420 big ones in the Audi RS 4.

This is the V-8 hot rod of the Audi A4 sedan line.

That Audi can pack this compact-class platform with a 4.2-liter V-8 is testament to the body structure.

AUDI RS4 QUATTRO - The RS 4 is a staggeringly fast outlaw with all-wheel drive and a six-speed manual transmission. It's a racecar for the street, and some of the engine technology comes from Audi's racecars. CNS Photo courtesy of Audi.

The A4 line ranges from the thrifty, 200 hp, turbocharged, 2.0-liter four-cylinder to the 255-hp, 3.2-liter V-6 and high-performance S4 with a 340-hp V-6.

The RS 4 is a staggeringly fast, speed-limit outlaw with all-wheel drive and a six-speed manual transmission. The engine has a supercharger-like whine, and the dual pipes roll with thunder. The car is rambunctious, rowdy, raw, hard-riding, socially unacceptable and completely enjoyable.

And to make the temptation even worse, there's a push-button Sport mode that sharpens throttle response and opens the pipes for faster exhaust outflow.Engaging Sport mode is like uncapping headers on a hot rod. The engine takes on a power-possessed tone, eyes roll back to the whites and in a deep snarl it calls out: "Satan's in the house. Time for fun."

How often do you get a spine-tingling shiver when driving a car? This one does that. And I'll take my recent week in the Audi RS 4 as a primer for Audi's R8 midengine sports car, which shares the powertrain, but in a lighter body.

It's a race car for the street, and some of the engine technology comes from Audi's race cars.

The hard suspension can wear on you after a day in the saddle, but when you are in the zone, it keeps the car stuck to the road along with all-wheel drive, which has a rear-drive bias. There is also a suite of electronic driver aids, such as an electronic stability program with electronic differential lock, traction control, electronic brake-force distribution and anti-lock brakes.

The electronic stabilization can be switched off in two stages. Stage one cancels traction control. Stage two is for those in-control individuals who race naked, without the car's safety net.

I tried to push some limits, but this car's loss-of-control threshold is high enough that the biggest reaction I managed was a little tire squeal.

The engine is high-revving, with peak horsepower at 7,800 rpm and peak torque at 5,500 rpm. It's not a pavement shredder away from the traffic light, but it is a screamer.

The engine uses high-pressure gasoline injection directly to the cylinders. Part of the screaming engine noise is induced by shifting at high revs. That's where this engine finds its groove.

And, mercy, the engine sounds fine at redline shifts. It doesn't take long to move through the gears, and active drivers will be shifting quite often. This power band isn't like the BMW M5 V-10 that has speed-limit-breaking range in second gear.

It doesn't take long to run through gasoline, either. The old-style EPA ratings gave it 13 mpg city and 21 highway. According to the car's computer, I was getting 15.9 combined - and I wasn't short-shifting to maximize fuel economy.

The car enjoys a workout, and the six-speed has an absolute feel to gear engagement. It's steely, somewhat like the crosscut gears of a race car. The clutch is light, and the gear box accommodating for rush-hour traffic jams.

Maybe it was just me, but I felt the shift points were even smoother in Sport mode.Audi's Dynamic Ride Control connects the dampers to trim body roll fore and aft and side to side. This car pulls through corners as tightly as the driver is able to hold onto the wheel without sliding out of the seat. I liked the well-boosted power steering, particularly when tooling around town, but not all will agree.

The brakes are enormous. The 14.4-inch cross-ventilated rotors with eight-piston calipers use four pistons and two brake pads on the inside and outside of each brake disc. The grabbing power is phenomenal - and a challenge to manage smoothly.

For a starting price of almost $67,000 - including a $2,100 gas-guzzler tax - the RS 4 is not a wallflower, particularly in Misano red pearl paint. There are a number of identifiers that announce this car as something special. It is lower than the standard S4 with wider wheel arches and flared sills, large grille for more active cooling, rear spoiler, dual oval tailpipes and gorgeous, 19-inch Pirelli P Zero tires on attractive wheels.

Satin aluminum trim is used on the mirrors, grille and elsewhere.

The engine bay is stuffed with motor, but also dressed up with red valve covers, carbon-fiber trim and chrome Audi rings. It's a nice presentation for show and tell. The M5's engine is dull, covered with a black plastic shroud and no flash.

There's also plenty of adornment to the Audi interior. Basic black leather seats are set off with thin, gray piping and an embossed RS 4 in the seat back. The headliner and carpets are also black, which makes for an AC-challenged cabin on a hot day. The seats should be perforated leather with ventilation.

The dashboard has carbon-fiber trim, and there's more satin aluminum elements.

I liked driving this car - slow or fast. The sightlines are good at all angles and the shoulder line is low enough to rest an elbow out the window. The turning circle is tight, and it's possible to cram three teenagers in the back seat. But they'd be the last ones to gripe about being stuffed into this car.

I seldom shed a tear when a test car goes back to the manufacturer. But when the delivery service took back the RS 4, I stood and listened as it drove away. It's that kind of car.

PLUSES: Wonderfully irresponsible driving partner.MINUSES: Black leather interior and black ceiling make for a hot car in warm weather; seats require perforated leather and ventilation. Center armrest is at the wrong height for some drives and not adjustable fore and aft.

CALLAWAY CABCallaway Cars unveiled its C16 Cabrio at the New York International Auto Show early this month.

Based on the C6 Corvette, the convertible variant of the C16 supercar has a 560 horsepower, supercharged 6.0 liter V-8 with 529 foot-pounds of torque. An optional 616 horsepower engine will give the car acceleration ability of 0-60 mph in 3.5 seconds, using the paddle-shift automatic transmission. Top speed is estimated to be just over 200 mph.

Six-speed manual or paddle-shift automatic transmissions are available with either engine.

The interior is upgraded with choices of German leather or Alcantara, Recaro seats and more. Paint color is up to the purchaser. Each C16 Cabrio is built to order, serialized and identified by a build plaque.

Pricing starts at $128,765 and includes a warranty for five years or 100,000 miles. Callaway C16 components are also available for 2005 to 2007 Corvettes. Details at www.callawaycars.com.

AUDI R8 PRICINGAudi of America announced pricing for its 2008 R8 sports car, which goes on sale in the fall and will be built in Neckarsulm, Germany. The starting price for an R8 with six-speed manual transmission is $109,000. The six-speed R-tronic automatic gearbox adds another $9,000, which may be incentive to learn how to use a clutch.

Expect the final price to bear what the market will pay.The midengine R8 - the first such design for Audi - uses a 420 horsepower, 4.2 liter V-8 engine, quattro all-wheel drive and 19-inch alloy wheels.

The fastest Audi yet, it has a 0-60 mph time of 4.4 seconds and a top speed of 187 mph.

Standard features include Audi magnetic ride, automatic bi-xenon headlights with LED daytime running lights, LED taillights and LED engine compartment lighting. Conveniences include automatic climate control, power and heated leather and Alcantara sport seats, cruise control and nine-speaker audio system with Sirius satellite radio.

RS6 ON THE TRACKAn Audi RS6 sedan has been seen in testing at the Nurburgring race track in Germany. Sources say the turbocharged S6 V-10 engine is putting out 520 to 550 horsepower. The car is expected to debut at the Frankfurt Motor Show in September.

Your car isn't clean until the tires are dressed, and the tires can't be dressed until they are clean. And a general wash usually won't clean the grime from rubber.Eagle One has two new tire- and wheel-detailing products for a one-two clean-and-shine.

The first step is All Wheel Tire & Wheel Cleaner, a spray bottle selling for $5.49. Give the tire a liberal drenching and watch as the sudsy spray turns murky brown on the rubber. The suds help the solution cling to tire and wheel, giving the solution time to penetrate. Wait 30 seconds, then hose off and dry.

The directions recommend eye protection (which I didn't use) and spraying only one wheel at a time when the wheels are cool. I sprayed both tires and wheels on one side of my vehicle without negative results. A light scrubbing helps but isn't always necessary.

The rubber was cleaned to a good, black base and ready for step two, Eagle One Tire Detailer ($7). The small squeeze bottle uses a sidewall-shaped sponge applicator. Tear off the bottle seal and squeeze the gel up and into the sponge, then swipe the tire.

The end result is good, but the process takes more effort than the directions indicate.

The gel clings to the rubber and avoids the old problem of overspray on the wheel from pump-bottle detailers. But the gel went on thick, and I used a clean towel to smooth and massage into all areas. The towel rubdown helped blunt the gleam to a gloss and cleaned up drips that might have been slung onto a freshly washed vehicle.

Still, the applicator is less messy than squeezing gel directly onto a towel, which gets all over hands, which tend to touch the vehicle and smudge the clean finish.Eagle One says the 8-ounce bottle of tire gel lasts twice as long as sprays and that the bottle will dress up to 40 tires, but not at the rate I had to use it.Details: www.eagleone.com or (800) 432-4531.

The first step is All Wheel Tire & Wheel Cleaner, a spray bottle selling for $5.49. Give the tire a liberal drenching and watch as the sudsy spray turns murky brown on the rubber. The suds help the solution cling to tire and wheel, giving the solution time to penetrate. Wait 30 seconds, then hose off and dry.

The directions recommend eye protection (which I didn't use) and spraying only one wheel at a time when the wheels are cool. I sprayed both tires and wheels on one side of my vehicle without negative results. A light scrubbing helps but isn't always necessary.

The rubber was cleaned to a good, black base and ready for step two, Eagle One Tire Detailer ($7). The small squeeze bottle uses a sidewall-shaped sponge applicator. Tear off the bottle seal and squeeze the gel up and into the sponge, then swipe the tire.

The end result is good, but the process takes more effort than the directions indicate.

The gel clings to the rubber and avoids the old problem of overspray on the wheel from pump-bottle detailers. But the gel went on thick, and I used a clean towel to smooth and massage into all areas. The towel rubdown helped blunt the gleam to a gloss and cleaned up drips that might have been slung onto a freshly washed vehicle.

Still, the applicator is less messy than squeezing gel directly onto a towel, which gets all over hands, which tend to touch the vehicle and smudge the clean finish.Eagle One says the 8-ounce bottle of tire gel lasts twice as long as sprays and that the bottle will dress up to 40 tires, but not at the rate I had to use it.Details: www.eagleone.com or (800) 432-4531.

The first step is All Wheel Tire & Wheel Cleaner, a spray bottle selling for $5.49. Give the tire a liberal drenching and watch as the sudsy spray turns murky brown on the rubber. The suds help the solution cling to tire and wheel, giving the solution time to penetrate. Wait 30 seconds, then hose off and dry.

The directions recommend eye protection (which I didn't use) and spraying only one wheel at a time when the wheels are cool. I sprayed both tires and wheels on one side of my vehicle without negative results. A light scrubbing helps but isn't always necessary.

The rubber was cleaned to a good, black base and ready for step two, Eagle One Tire Detailer ($7). The small squeeze bottle uses a sidewall-shaped sponge applicator. Tear off the bottle seal and squeeze the gel up and into the sponge, then swipe the tire.

The end result is good, but the process takes more effort than the directions indicate.

The gel clings to the rubber and avoids the old problem of overspray on the wheel from pump-bottle detailers. But the gel went on thick, and I used a clean towel to smooth and massage into all areas. The towel rubdown helped blunt the gleam to a gloss and cleaned up drips that might have been slung onto a freshly washed vehicle.

Still, the applicator is less messy than squeezing gel directly onto a towel, which gets all over hands, which tend to touch the vehicle and smudge the clean finish.Eagle One says the 8-ounce bottle of tire gel lasts twice as long as sprays and that the bottle will dress up to 40 tires, but not at the rate I had to use it.Details: www.eagleone.com or (800) 432-4531.

CHRYSLER ADDS "BACKSEAT" TVChrysler will be the first and only auto manufacturer to offer Sirius Backseat TV in 2008.

Family-type programming on three channels will be available from Nickelodeon, Disney Channel and Cartoon Network beginning in the redesigned 2008 Chrysler Town & Country and Dodge Grand Caravan minivans. The Chrysler 300, Dodge Charger, Dodge Magnum, Jeep Commander and Jeep Grand Cherokee will also have the option.

Backseat TV uses an in-vehicle satellite video receiver and two small roof-mounted antennas. Programming is displayed on second- and third-row video screens. Front-seat occupants can listen to Sirius satellite radio, but when the vehicle is parked - not in gear - front-seat occupants can watch TV on the MyGIG "infotainment" screen in the instrument panel.

The Sirius Backseat TV option will be $470, including a year of service, when packaged with the rear-seat entertainment system and Sirius satellite radio.After the first year, Sirius TV service will cost $7 a month when packaged with Sirius Radio ($12.95 a month).